Molded top and bottom dish members for petri dishes are usually produced in stack molds wherein the dish members are molded in back-to-back relation with the dish openings of the top and bottom members positioned in oppositely facing directions. The top and bottom members are then usually separately conveyed in flat horizontal positions to an assembly location wherein the top members are manually or automatically placed over the bottom members. Assembly apparatus for this procedure is disclosed in U.S. Pat. No. 3,938,675. The use of this apparatus is unsatisfactory for two reasons. First, it is usually located a considerable distance from the molding apparatus. This enables the top and bottom dish members to become contaminated prior to assembly of the finished petri dish necessitating a subsequent sterilization step. Second, it is a rather complex apparatus requiring many moving parts.
Apparatus is known for bringing various container members into telescoping relationship. U.S. Pat. No. 3,844,896 discloses apparatus for removing top members from petri dishes and then replacing them. U.S. Pat. No. 3,983,616 discloses apparatus for assembling lids on glass containers. U.S. Pat. No. 3,994,059 discloses apparatus for assembling oil filter components.
There is no known prior art which discloses or suggests the assembly of top and bottom petri dish members while still at an elevated molding temperature by positioning such members in spaced, substantially coaxial face-to-face relation, moving such members along a predetermined path, and as such members are moved along said path, moving them toward each other into telescopic assembled relation.